バッファ層に CeO<sub>2</sub>/Y<sub>2</sub>O<sub>3</sub>/CeO<sub>2 </sub>を用いた Ni めっき Cu/SUS316 貼合せテープ上への YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7 </sub>超電導厚膜の作製

Abstract

In this study, we attempted to install CeO 2 /Y2 O3 /CeO2 buffer layers, where the thicknesses of the CeO2 and Y 2O3 are10 and 250 nm respectively, instead of the CeO 2/YSZ (Y 2O3 stabilized ZrO 2)/CeO2 buffer layer architecture for YBCO (YBa 2 Cu3 O7 ) coated conductors using Ni-electroplated {100}<001> textured Cu and SUS316 laminated tape. Since the diffusion coefficient of oxygen in Y 2O3 is much smaller than that in YSZ and CeO 2, Y 2O3 seems to be a more favorable buffer layer material. We obtained a Jc of 1.0 MA/cm2 for the YBCO/Y 2 O3/Ni-electroplated Cu/SUS 316 laminated tape. However, the Δφvalue of the Y 2O3 layer deposited on the Ni layer increased by 1°compared with that of the Ni layer, and the Δφvalue of the YBCO layer on the Y 2O3 layer increased by 1.5°compared with that of the Y 2O3 layer. To avoid the degradation of the crystal orientations, we inserted very thin CeO2 layers of 10 nm between the Ni and the Y 2O3 layers, and between the Y 2O3 and the YBCO layers. The Jc of the 1 μm-thick YBCO layer prepared on the CeO 2 /Y2 O3 /CeO2 -buffered Ni-electroplated {100}<001> textured Cu/SUS316 laminated tape reached 2.1 MA/cm2 (Ic of 210 A-cm width) at 77 K in a self-field.